Pasteur eventually decided to work on diseases. One disease in which he studied is called chicken cholera. During this work, a large amount of the bacteria responsible for causing this desease spoiled and failed to infect some of the chickens he had been experimenting on. After re-injecting these healthy chickens with fresh bacteria, he discovered that he could not infect them. This lead him to beleive that the weakened bacteria had caused the chickens to become immune to the disease. In the 1870s, he dicieded to apply this method of immunization to a disease that affected cattle called anthrax. Eventually his studies lead to the creation of an anthrax vaccine. Even though dead or weakened strands of viruses were previously used for curing deseases, Pasteur coined the term ''vaccine". Eventually, he discovered the first vaccine for rabies by growing the virus in rabbits, and then weakining it by drying the affected nerve tissue. Because of his overall study in germs, Pasteur encouraged doctors to sanitize their hands and equipment before surgery. Prior to this, few doctors or their assistants practiced these simple procedures.